GTBL042-09 GTBL042-Callister-v3 October 4, 2007 11:53

2nd Revised Pages

Chapter 9 Failure

An oil tanker that fractured in a brittle manner by crack propagation around its girth.

(Photography by Neal Boenzi. Reprinted with permission fromThe New York Times.)

WHY STUDYFailure?

The design of a component or structure often calls upon

the engineer to minimize the possibility of failure. Thus,

it is important to understand the mechanics of the

various failure modes—i.e., fracture, fatigue, and

creep–and, in addition, to be familiar with appropriate

design principles that may be employed to prevent

in-service failures. For example, we discuss in Sections

M.7 through M.9 of Web Module M, material selection

and processing issues relating to the fatigue of an

automobile valve spring.

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